Cephalosporin intermediates

ABSTRACT

Stable, crystalline cephalosporin intermediates of the formula ##STR1## wherein X is HI or HCl and Nu and Nu.sup.⊕ are certain N-containing heterocyclic rings attached via a sulfur atom or a ring nitrogen atom, respectively, which are substantially free of the Δ 2  isomer; processes for, and intermediates in, the preparation of the above compounds; and processes for the preparation of broad-spectrum cephalosporin antibiotics.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of our co-pending applicationSer. No. 767,561, filed Aug. 20, 1985 abandoned.

SUMMARY OF THE INVENTION This invention relates to temperature stable,crystalline salts of a cephalosporin intermediate having the formula##STR2## wherein X is HI or HCl, which are substantially free of the Δ²isomer, and which are convertible into broad specturm cephalosporinantibiotics without the necessity of a carboxyl group deblocking step.This invention also relates to a method for making the salts of FormulaI, to intermediates in the preparation of the salts of Formula I, and toa method of converting a salt of Formula I into broad spectrumcephalosporin antibiotics. DESCRIPTION OF THE PRIOR ART

U.S. Pat. No. 4,406,899, issued Sept. 27, 1983 to Aburaki et al.,discloses compounds of the formulae ##STR3## wherein Ph is phenyl, and##STR4## or an N-silyl derivative thereof, wherein B¹ is hydrogen or aconventional carboxyl-protecting group. These compounds are notexemplified in the patent, but are disclosed by structural formulaeonly, as intermediates in an alternate reaction scheme for thepreparation of certain cephalosporins (by acylation and then deblockingof the protected carboxyl group). The reaction scheme actuallyexemplified did not utilize these compounds (and also requireddeblocking of the protected carboxyl group as the final step). Each ofthe final products of U.S. Pat. No. 4,406,899 required a chromatographicpurification step to separate the mixture of Δ² and Δ³ isomers whichwere produced.

U.S. Pat. No. 4,168,309, issued September 18, 1979 to Barry E. Ayres,discloses compounds of the formula ##STR5## wherein R"' is acarboxyl-protecting group; R¹, taken together with the carbon atom towhich it is attached, forms an optionally substituted saturated orpartially saturated 4-10 membered heterocyclic ring which may containone or more further heteroatoms selected from 0, N and S; the dottedline indicating a ceph-2-em or a ceph-3-em compound; and X⁻ representingan anion; and acid addition salts or an N-silylated derivative thereof.

These compounds are not exemplified but are disclosed by structuralformula only as intermediates in an alternative synthesis of certaincephalosporins (by acylation and then deblocking of the protectedcarboxyl group). The reaction scheme actually exemplified did notutilize these compounds (and also required deblocking of the protectedcarboxyl group as a final step).

The use of blocked carboxyl groups in the processes of the above twopatents has the disadvantage of requiring deblocking after acylatingwhereby acyl group is lost in the deblocking step due to less than 100%yield in the deblocking step.

U.S. Pat. No. 4,223,135, issued September 16, 1980 to Derek WalKee etal., discloses compounds of the formula ##STR6## in which B is chloro,methoxy or --CH₂ E, E is hydrogen, ##STR7## in which Z is an optionallysubstituted 5- or 6-membered heterocyclic ring containing 2-4 N atomsand zero or one atom selected from 0 and S, the S atom of -SZ beingconnected to a carbon atom of the heterocyclic ring Z, and A istrimethylsilyl or an easily cleavable ester-protecting group.

The compounds are prepared by adding dry carbon dioxide to a solution ofa compound of the formula ##STR8## wherein A and B are as describedabove, in an inert organic solvent which is preferably methylenechloride.

U.S. Pat. Nos. 4,316,017, which is a continuation-in-part of a divisionof 4,223,135, has a substantially identical disclosure.

U.S. Pat. No. 4,336,253, issued June 22, 1982 to William H. W. Lunn,discloses compounds of the formula ##STR9## and their preparation byreaction of a compound of the formula ##STR10## with a silylating agentsuch as trimethylsilylacetamide, bistrimethylsilylacetamide, or thelike, to produce a compound of the formula ##STR11## reacting thecompound of Formula III with trimethylsilyl iodide to produce a compoundof the formula ##STR12## and then reacting the compound of Formula IVwith ##STR13## to produce a compound of Formula I.

Solvents suitable for the reactions to produce Compounds III and IV arestated to be chlorinated hydrocarbons and lower alkyl nitriles.

U.S Pat. Nos. 4,379,787, 4,382,931 and 4,382,932 to William H. W. Lunnet al. are to analogous compounds and processes, wherein R is, forexample, an amino-substituted oxazole, oxadiazole or isoxazole ring, andthe 3-substituent is, for example, optionally substituted pyridine,quinoline or isoquinoline.

South African Pat. No. 84/3343, issued Oct. 25, 1984, discloses aprocess for the preparation of cephalosporins of the formula ##STR14##in which R is thiazolyl or 1,2,4-thiadiazolyl radical, R¹ is hydrogen ormethoxy, R² is one of numerous substituents known in the cephalosporinart, and A is optionally substituted quinolinium, isoquinolinium orpyridinium. The compounds of Formula I are prepared by reacting acompound of the formula in which R⁸ is hydrogen or an amino-protectinggroup and R⁷ is "a group which can be replaced by the base correspondingto radical A", with the base corresponding to radical A in the presenceof a trialkyliodosilane, to form a compound of the formula which (afterremoval of any amino-protective group) is subsequently acylated with anacid of the formula ##STR15## Suitable R⁷ groups which are mentionedinclude acetoxy, propionyloxy, chloroacetoxy, acetylacetoxy andcarbamoyloxy. Suitable solvents which are mentioned include methylenechloride, chloroform, dichloroethane, trichloroethane, carbontetrachloride, acetonitrile, propionitrile and frigands. Methylenechloride is most preferred.

It is acknowledged in the patent that the general process is known, butit is stated that the inventors have found that the yields aresurprisingly high if the nucleophilic displacement reaction on CompoundII (to form Compound III) is carried out by first adding an excess ofthe base corresponding to radical A (up to a 20-fold excess) and thenadding the trialkyliodosilane (up to a 10-fold excess).

In the W. German priority application No. (P3316798.2, filed May 7,1983) for this S. African application, the solvents listed are the sameas above, except that "frigand" is called "frigen". The Merck Index,10th Edition, lists Frigen 11, Frigen 12 and Frigen 114, and shows themas other names for Freon 11, Freon 12 and Freon 114 which aretrichlorofluoromethane, dichloro-difluoromethane and1,2-dichloro-1,1,2,2-tetrafluoroethane, respectively.

COMPLETE DESCRIPTION

The compounds of the formula ##STR16## wherein X is HI or HCl, whenprepared as described herein, are crystalline, temperature stable andsubstantially free of the corresponding Δ² isomer. As a result of beingsubstantially free of the Δ² isomer, they are convertible (by acylation)to broad spectrum cephalosporins which themselves are substantially freeof the Δ² isomer, without the need for chromatographic separation Δ² andΔ³ isomers. As a result of their temperature stability, they may beisolated and stored, and converted to the end products when desired. Anadditional advantage of the intermediates of Formula I is that they donot require blocking (protection) of the carboxyl group prior toacylation or deblocking (deprotection) of the carboxyl group afteracylation, thus offering process efficiency.

The oompounds of Formula I may be prepared by treating a solution of thecompound of the formula ##STR17## in 1,1,2-trichlorotrifluoroethane(Freon TF) with a (lower)-alkanol or water to remove the trimethylsilylgroups, followed by HCl or HI to form the hydrochloride or hydriodidesalt. It is preferred to use a (lower)alkanol for removal of thetrimethylsilyl groups, and most preferably methanol. The reaction isconducted at a temperature of from about -10° C. to about 25° C., andpreferably at a temperature of from about 0° C. to about 10° C. Fromabout 2 to about 5 equivalents of methanol are used per equivalent ofCompound II, and preferably about 3 to about 4 equivalents of methanol.

The compound of Formula II may be prepared by reacting a solution of thecompound of the formula ##STR18## in Freon TF with N-methylpyrrolidine(NMP). It has surprisingly been found that the use of Freon TF assolvent produces Compound II which is substantially free of the Δ²isomer, while commonly used solvents such as methylene chloride, carbontetrachloride, chloroform or dioxane produce Compound II which containslarge amounts of the undesirable Δ² isomer (e.g. 50% Δ² isomer).

The reaction is conducted at a temperature of from about -10° C. toabout 25° C., and preferably from about 0° C. to about 10° C. Althoughit is possible to use greater or lesser amounts of N-methylpyrrolidine,we obtain highest purity of product when about 1 equivalent of NMP isutilized per equivalent of Compound IIIa.

The compound of Formula IIIa may be prepared by reaction of a solutionof the compound of the formula ##STR19## in Freon TF or methylenechloride, with trimethylsilyl iodide (TMSI). Surprisingly, thesesolvents yield Compound IIIa which

is substantially free of the Δ² isomer, while similar common solvents(e.g. 1,2-dichloroethane) give Compound IIIa containing significantamounts of the undesirable Δ² isomer (e.g. 25%). Other common solventssuch as chlorobenzene, dioxane, carbon tetrachloride, and the like, alsogive significant amounts of the undesirable Δ² isomer.

The reaction is conducted at a temperature of from about 5° C. to about40° C., but preferably is conducted at ambient temperature forconvenience. The TMSI may be utilized in an amount of from about 0.9 toabout 1.5 equivalents per equivalent of Compound IVa. We prefer to usefrom about 1.0 to about 1.2 equivalents of TMSI.

The compound of Formula IVa may be prepared by reacting7-aminocephalosporanic acid (7-ACA), i.e. the compound of the formula##STR20## with hexamethyldisilazane (HMDS) in the presence of from about0.01 to about 0.1 equivalents of TMSI per equivalent of 7-ACA, in FreonTF or methylene chloride, at a temperature from room temperature to theboiling point of the solvent. Preferably, the reaction is conducted atreflux. The HMDS may be used in an amount of from about 0.95 to about1.4 equivalents per equivalent of 7-ACA, and preferably from about 1.0to about 1.3 equivalents of HMDS per equivalent of 7-ACA. We most preferto utilize 1.2 equivalents of HMDS.

In an alternate preparation of Compound II, a solution of Compound IVain Freon TF is reacted with N-methyl-N-trimethyl-silylpyrrolidinioiodide having the formula ##STR21## at a temperature of from about 10°C. to about 40° C. For convenience, we prefer to conduct the reaction at35° C. The compound of Formula VI may be used in an amount of from about1.0 to about 2.0 equivalents per equivalent of Compound IVa, andpreferably from about 1.2 to about 1.5 equivalents of Compound VI perequivalent of Compound IVa. If desired, a small amount of imidazole(e.g. 0.1 equivalents) may be added to the reaction mixture to shortenthe reaction time. We have found that, when preparing Compound II by thereaction of Compound IVa with Compound VI, Compound IIIA can be detectedin the reaction mixture during the reaction in small amounts (by NMRanalysis).

The compound of Formula VI may be prepared by reactingN-methylpyrrolidine with about an equimolar amount of TMSI in Freon TFas solvent, at a temperature of from about -10° C. to about 25° C. Weprefer to conduct the reaction at a temperature of from about 0° C. toabout 5° C. The reaction ratio of NMP and TMSI may be varied, but weobtain excellent results by utilizing equimolar amounts.

In a preferred reaction scheme, the compounds of Formula I are preparedfrom 7-ACA in a "one pot" reaction, i.e. without the isolation of anyintermediates. Although certain of the individual reaction steps may beconducted in solvents other than Freon TF, as indicated above, othersrequire the use of Freon TF. Accordingly, when conducting the "one pot"reaction, the reaction is conducted in Freon TF.

In conducting the reaction sequence described herein, we have found itnecessary to proceed via the 3-iodomethyl Compound IIIa, rather than thecorresponding 3-chloromethyl or 3-bromomethyl analog. We havesurprisingly found that the reaction of Compound IVa with trimethylsilylchloride or trimethylsilyl bromide gives little of the expected3-chloromethyl or 3-bromomethyl analog of Compound IIIa, e.g. a maximumof about 5-15% even after refluxing for 10 days.

Although the quaternization of Compound IIIa with NMP to produceCompound II (and, subsequently, a compound of Formula I), must beconducted in Freon TF in order to obtain Compound II (and I) which aresubstantially free of the Δ² isomer, Compound IIIa may be reacted withother nucleophilic agents in Freon TF or methylene chloride solution toproduce analogs of Compound II. After treatment with a (lower)alkanoland optional salt formation with, for example, HCl or HI, there areobtained analogs of Compound I which have the formula ##STR22## in whichX is, for example, HCl or HI, --Nu is ##STR23##

The compounds of Formula VIIa and VIIb also may be prepared by thereaction of the compound of the formula ##STR24## by the same proceduredescribed above for their preparation from Compound IIIa. However, thecompound of formula IITb is highly insoluble in Freon TF, so that thereaction must be conducted in methylene chloride. For that reason, whenprepared from Compound IIIb, the compounds of Formula VIIb in which-.sup.⊕ Nu is the N-methylpyrrolidinio moiety (i.e. the compounds ofFormula I) are predominantly the undesirable Δ² isomer.

The compound of Formula IIIb may be prepared, in Freon TF or methylenechloride, from the compound of the formula ##STR25## by the sameprocedure described above for the preparation of Compound IIIa fromCompound IVa. The compound of Formula IVb may be prepared by bubblingcarbon dioxide gas into a solution of Compound IIIa in Freon TF ormethylene chloride, in the presence of a small amount (e.g. 0.1equivalent) of pyridine hydrochloride.

The compounds of Formula I, VIIa and VIIb are readily converted to broadspectrum antibiotics by acylation with the appropriate side-chain acid.For example, a compound of Formula I (X =HCl or HI) is converted to7-[α-(2-aminothiazol-4-yl)-α-(Z)-methoxyiminoacetamido]-3-[(1-methyl-1-prrolidinio)-methyl]-3-cephem-4-carboxylate (VIII) by N-acylating with 1-benzotriazolyl(Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetate active ester. Thereaction equation is set forth below. ##STR26## This reaction is readilycarried out in the presence of N,N-dimethylaniline in dimethylformamideat room temperature over a period of 10-20 hours; or by dissolving (I)in water and dimethylformamide and adding sodium bicarbonate with icecooling, and reacting at room temperature for about 30 minutes to about5 hours; or by dissolving (I) in water, cooling to 5°-15° C., addingNaOH dropwise to pH 5.5-6, adding tetrahydrofuran, adding sodiumhydroxide to adjust the pH to 6.7-6.9, adding the active ester reactantand reacting for 1 to 5 hours at room temperature. The active ester is aknown compound and is described in Hoechst, Japan Kokai No. 54-95593(7/28/79) and German Application No. 2758000.3 (12/24/77). The utilityof the compound (VIII) is shown in Aburaki et al., U.S. Pat. No.4,406,899.

The compounds of Formulae VIIa and VIIb may be acylated in a similarmanner to produce broad spectrum cephalosporins.

EXAMPLE 1 (6R,7R)-Trimethylsilyl7-(Trimethylsilyl)amino-3-acetoxymethylceph -3-em-4-carboxylate Method A

An oven-dried flask and Friedrich's condenser were cooled to ambienttemperature under a stream of dry nitrogen. The flask was then chargedwith 50.0 g (184 mmoles) of 7-ACA (97.2% purity) and 400 ml of dry1,1,2-trichlorotrifluoroethane (Freon TF, dried over molecular sieves).To the resulting slurry was added 46.5 ml (222 mmoles, 1.2 equivalents)of 98% 1,1,1,3,3,3-hexamethyldisilazane (HMDS) and 0.80 ml (5.6 mmoles,0.03 equivalents) of iodotrimethylsilane (TMSI) with good stirring andwith protection from moisture. The slurry was vigorously heated underreflux for 16-18 hours, after which time it was cooled to ambienttemperature. A ^(l) H NMR spectrum of an aliquot of the slightly hazyreaction mixture showed >95% conversion to the desired product. NMR (CD₂Cl₂, 360 MHz) δ0.23 (s, 9H, N-Si(CH₃)₃), 0.38 (s, 9H, --COOSi(CH₃)₃),0.38 (s 9H, COOSi(CH₃).sub. 3), 1.51 (d, 1H, J=13.6 Hz, NH--), 2.09 (s,3H, --COCH₃), 3.41 (d, 1 H, J=18.3 Hz, --SCH₂ --), 3.61 (d, lH, J=18.3Hz, --SCH₂), 4.80 (dd, 1 H, J=4.5, 13.6 Hz, --COCH(NHSi(CH₃)₃), 4.83 (d,lH, J=13.2 Hz, --CH₂ OCOCH₃), 4.91 (d, lH, J=4.5 Hz,--COCH(NHSi(CH₃)3CH--), 5.11 (d, lH, J=13.2 Hz, --CH₂ OCOCH₃).

Method B

An oven-dried flask and Friedrich's condenser were cooled to ambienttemperature under a stream of dry nitrogen. The flask was charged with10.0 g (36.7 mmoles) of 7-ACA (97.2% purity) and 80 ml of dry Freon TF(dried over molecular sieves). To the resulting slurry was added 9.3 ml(44.1 mmoles, 1.2 equivalents) of 98% HMDS and 44 ml (1.1 mmoles, 0.03equivalent) of a 0.025M solution of HI in Freon TF (prepared by bubblingHI into dry Freon TF and titrating the resulting saturated solution to aphenolphthalein endpoint). The slurry was vigorously heated under refluxwith good stirring and with protection from moisture for 22 hours, afterwhich time it was cooled to ambient temperature. A ¹ H NMR spectrum (CD₂Cl ₂, 360 MHz showed >95% conversion to the desired product.

Method C

An oven-dried flask and Friedrich's condenser were cooled to ambienttemperature under a stream of dry nitrogen. The flask was charged with10.0 g (36.7 mmoles) of 7-ACA (97.2% purity) and 80 ml of drydichloromethane (from sieves). To the resulting slurry was added 9.3 ml(44.1 mmoles, 1.2 equivalents) of 98% HMDS and 0.16 ml (1.1 mmoles, 0.03equivalent) of TMSI with good stirring and with protection frommoisture. The slurry was vigorously heated under reflux for 5 hours,after which time the slightly hazy reaction mixture was cooled toambient temperature A ^(l) H NMR spectrum (CD₂ Cl₂, 360 MHz) showed >95%conversion to the desired product.

EXAMPLE 2 (6R,7R)-Trimethylsilyl7-[((Trimethylsilyl)oxy)carbonyl]amino-3-acetoxymethylceph-3-em-4-carboxylateMethod A

To a reaction mixture of (6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate in FreonTF (prepared according to Method A of Example 1; 10.0 g input 7-ACA) wasadded 410 mg (3.5 mmoles, 0.10 equivalent) of freshly prepared pyridinehydrochloride under a blanket of dry nitrogen at ambient temperature.Next, dry carbon dioxide gas was gently bubbled into the reactionmixture through a capillary pipet for 24 hours with good stirring. Afterthis time, the resulting slurry was filtered with positive nitrogenpressure through a Schlenk funnel, and the collected solid was washedwith fresh, dry Freon TF (2×25 ml) and was partially dried under suctionwith a positive stream of nitrogen for 15 minutes. Further drying atambient temperature at 0.05 mm Hg for 5 hours gave 13.30 g (85%) oflight yellow, crystalline, moisture sensitive (6R,7R)-trimethylsilyl7-[((trimethylsilyl)oxy)carbonyl]amino-3-acetoxymethylceph-3-em-4-carboxylate:IR(CH₂ Cl₂) 1790, 1743, 1709, 1511, 1250, 1232 cm⁻¹ ; NMR(CD₂ Cl₂, 360MHz) δ0.31 (s, 9H, --NHCOOSi(CH₃)₃), 0.36 (s, 9H, --COOSi(CH₃)₃), 2.08(s, 3H, --COCH₃), 3.44 (d, 1H, J=18.6 Hz, --SCH₂), 3.63 (d, 1H, J=18.6Hz, --SCH₂), 4.85 (d, 1H, J=13.4 Hz, --CH₂ OAc), 5.02 (d, 1H, J=5.1 Hz,--CHCH(--N)SCH₂), 5.11 (d, 1 H, J=13.4 Hz, --CH₂ OAc), 5.54 (d, 1H,J=9.7 Hz, --CONHCH(CO--)CH--), 5.63 (dd, 1H, J=5.1, 9.7 Hz,--CONHCH(CO--)CH--).

Method B

Dry carbon dioxide gas was gently bubbled into a reaction mixture of(6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate in drydichloro-methane (prepared according to Method C of Example 1; 5.0 ginput 7-ACA) with good stirring for 12 hours at ambient temperature. A^(l) H NMR spectrum of an aliquot of the resulting solution showed >95%conversion to the desired (6R,7R)-trimethylsilyl7-[((trimethylsilyl)oxy)carbonyl]amino-3-acetoxymethylceph-3-em-4-carboxylate.

EXAMPLE 3 (6R,7R)-Trimethylsilyl7-(Trimethylsilyl)amino-3-iodomethylceph-3-em-4-carboxylate Method A

A total of 30 ml (210 mmoles, 1.15 equivalents) of TMSI was added in aslow stream at ambient temperature to a reaction mixture of(6R,7R)-trimethylsilyl 7-(trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate in Freon TF (prepared according to Method A ofExample 1; 50.0 g input 7-ACA) under a blanket of dry nitrogen. Theprogress of the reaction was monitored by ^(l) H NMR (acetate region).After 1 hour, the slurry was filtered through a Schlenk tube underpositive nitrogen pressure. The collected solid was washed with freshFreon TF (1 ×100 ml). An aliquot of the filtrate gave the following ¹ HNMR spectrum in support of the in situ generated (6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-iodomethylceph-3-em-4-carboxylate: (CD₂ Cl₂,360 MHz) δ .16 (s, 9H, NHSi(CH₃)₃), 0.40 (s, 9H, --COOSi(CH₃)₃), 1.51(d, 1H, J=13.4 Hz, NH), 3.54 (d, 1H, J=17.9 Hz, --SCH₂ --), 3.80 (d, 1H,J=17.9 Hz, --SCH₂), 4.37 (d, 1H, J=9.2 Hz, --CH₂ I), 4.49 (d, 1H, J=9.2Hz, --CH₂ I), 4.75 (dd, 1H, J=4.6, 13.4 Hz, --COCH(NHSi(CH₃)₃), 4.89 (d,1 H, J=4.6 Hz, --COCH(NHSi(CH₃)₃)CH--).

Method B

To a stirred solution of (6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate indichloromethane (prepared according to Method C of Example 1; a 20 mlaliquot of the reaction mixture (11.7 mmoles starting material contentwas used for this reaction) under a blanket of nitrogen at ambienttemperature was added 1.66 ml (11.7 mmoles, 1.0 equivalent) ofiodotrimethylsilane (TMSI) in a slow stream. After stirring for anadditional 1 hour, the ^(l) H NMR spectrum (acetate region) of analiquot showed >95% conversion to the desired (6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-iodomethlceph-3-em-4-carboxylate.

EXAMPLE 4 (6R,7R)-Trimethylsilyl7-[((Trimethylsilyl)oxy)carbonyl]amino-3-iodomethylceph-3-em-4-carboxylate

To a stirred solution of (6R,7R)-trimethylsilyl 7-[(trimethylsilyl)oxy)carbonyl]amino-3-acetoxymethylceph-3-em-4-carboxylate indichloromethane (prepared according to Method B of Example 2; 5.0 ginput 7-ACA) was added 3.0 ml (21.1 mmoles, 1.15 equivalents) of TMSI ina slow stream at ambient temperature under a blanket of dry nitrogen.The progress of the reaction was monitored by ^(l) H NMR (acetateregion). After a total of 65 minutes, the ^(l) H NMR spectrum of analiquot of the dark solution showed >95% conversion to the desired(6R,7R)-trimethylsilyl7-[((trimethylsilyl)oxy)carbonyl]amino-3-iodomethylceph-3-em-4-carboxylate:NMR (CD₂ Cl₂) δ0.27 (br s, 9H --NHCOOSi(CH₃)₃), overlapped with CH₃COOSi(CH₃)₃), 0.37 (s, 9H, --COOSi(CH₃)₃), 3.57 (d, 1H, J=18.1 Hz,--SCH₂), 3.80 (d, 1H, J=18.1 Hz, --SCH₂), 4.34 (d, 1H, J=9.2 Hz, --CH₂I), 4.51 (d, 1 H, J=9.2 Hz, --CH₂ I), 5.00 (d, 1H, J=4.6 Hz,--COCH(N)CH(N)SCH₂ --); the remainder of the spectrum was obliterated byprotonic dichloromethane.

EXAMPLE 5 N-Methyl-N-trimethylsilylpyrrolidinio Iodide

An oven-dried flask was cooled to ambient temperature under a stream ofpositive nitrogen. The flask was charged with 25 ml of dry Freon TF(dried over molecular sieves) and 1.42 ml (10.0 mmoles, 1.0 equivalent)of TMSI. The resulting solution was cooled to 0-5° C. under a blanket ofdry nitrogen. A total of 1.04 ml (10.0 mmoles, 1.0 equivalent) of dry,97% N-methylpyrrolidine (dried over molecular sieves) was added dropwiseand the resulting slurry was stirred at 0°-5° C. under a nitrogenblanket for 30 minutes. After this time, the slurry was filtered underpositive nitrogen pressure through a Schlenk funnel, and the collectedsolid was washed with fresh, dry Freon TF (2×25 ml). The filter cake waspartially dried under a positive stream of nitrogen for 15 minutes.Further drying at ambient temperature for 12 hours at 0.05 mm Hgafforded 2.51 g (89%) of N-methyl-N-trimethylsilylpyrrolidinio iodide asa colorless, extremely air sensitive solid: C.sub. 8 H₂₀ INSi requires44.49% iodide; found, 44.40% iodide (iodide ion chromatographyanalysis).

In a separate experiment, the reaction was conducted generally as above,except that 0.40 ml (10.0 mmoles, 1.0 equivalent) of methanol was addeddropwise to the slurry of the salt in Freon TF at 0°-5° C. The resultingheterogeneous mixture was stirred at 0°-5° C. under a nitrogen blanketfor an additional 30 minutes. The slurry was filtered under anhydrousconditions through a Schlenk funnel. The filter cake was washed withfresh Freon TF (2×25 ml) and was dried at ambient temperature for 3hours at 0.05 mm Hg. The isolated solid (1.93 g, 91%) was identified asN-methylpyrrolidinio iodide, mp 80°-82° C. (uncorrected). An authenticsample of this salt was prepared independently by gassing a solution ofN-methylpyrrolidine in Freon TF with hydrogen iodide. The isolated solidhad mp 83.5°-85.5° C. (uncorrected). The 360 MHz ¹ H NMR spectrum ofthis material (D₂ O) was consistent with the spectrum observed for thesalt isolated from the methanol quenched reaction.

The 360 MHz ¹ H NMR spectrum of the filtrate from the methanol quenchedreaction showed, as the major components, methoxytrimethylsilane andmethyl iodide (integration ratio 17/1), as well as a small amount ofhexamethyldisiloxane.

EXAMPLE 6(6R,7R)-7-Amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em-4-carboxylateMonohydrochloride Method A

To a solution of (6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-iodomethylceph-3-em-4-carboxylate in Freon TF(prepared according to Method A of Example 3; 50.0 g input 7-ACA) at0°-5° C. under a blanket of dry nitrogen was added 19.0 ml (183 mmoles,1.0 equivalent) of dry 97% N-methylpyrrolidine (NMP, dried overmolecular sieves) dropwise at a rate sufficient to maintain a reactiontemperature of <10° C. The resulting slurry was stirred vigorously at0°-5° C. for 15 minutes following complete addition. After this time, anadditional 100 ml of dry Freon TF was added to facilitate agitation.Next, 25 ml (615 mmoles, 3.35 equivalents) of methanol was addeddropwise at a rate sufficient to maintain a reaction temperature of <10°C. The slurry was vigorously stirred at 0°-5° C. for an additional 15minutes. The reaction mixture was filtered and the collected solid waswashed with fresh Freon TF (1×100 ml) followed by partial drying undersuction for 15 minutes. Further drying in vacuo at ambient temperaturefor 16 hours gave 71.3 g (>100%) of crude product.

To this material was added 200 ml of water. The pH of the slurry (2.40)was lowered to 0.50 by dropwise addition of concentrated HCl. A total of10.0 g of decolorizing carbon was added, and the slurry was stirred atambient temperature for 15 minutes. The decolorizing carbon was removedby filtration through a celite pad (10.0 g), and the pad was washed withfresh deionized water (1×25 ml). The product was precipitated from theaqueous solution by dropwise addition of 5 volumes of acetone. Theslurry was cooled to 0°-5° C. and was maintained at this temperature for30 minutes. The slurry was vacuum filtered, sequentially washed with 50ml of cold (0°-5° C.) 5/1 acetone/water and acetone (2×50 ml), and waspartially dried under suction for 15 minutes. Further drying in vacuoafforded 23.3 g (39%) of snow white, crystalline(6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)-methylceph-3-em-4-carboxylate monohydrochloride: HPLC assayed as 96.3% versus thestandard lot; NMR (D₂ O, , 360 MHz, D₂ O/H₂ O supressed) δ2.14-2.32(envelope, 4H, --N(CH₃)CH₂ CH₂ --), 3.00 (s, 3H, NCH₃), 3.46-3.67 (m,5H, --N(CH₃)CH₂ CH₂ ; SCH₂), 3.96 (d, 1H, J=16.9 Hz, --SCH₂), 4.09 (d,1H, J=13.9 Hz, =CCH₂ N--), 4.73 (d, 1H, J=13.9 Hz, =CCH₂ N--), 5.21 (d,1H, J=5.1 Hz, --COCHCHS--), 5.41 (d, 1H, J=5.1 Hz, --COCHCHS--).

Method B

An oven-dried flask was cooled to ambient temperature under a stream ofdry nitrogen. The flask was charged with 15.7 ml (110 mmoles, 1.5equivalents) of TMSI and 140 ml of dry Freon TF (dried over molecularsieves). The resulting solution was cooled to 0°-5° C., and 10.7 ml (103mmoles, 1.4 equivalents) of 97% NMP was added dropwise so as to maintaina reaction temperature of <10° C. Following the addition, the slurry wasstirred at 0°-5° C. for 30 minutes under a nitrogen blanket. After thistime, the slurry was allowed to warm to room temperature.

A reaction mixture containing (6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate (preparedaccording to Method A of Example 1; 20.0 g input 7-ACA) was added bycannula as quickly as possible to the NMP/TMSI slurry at ambienttemperature. The resulting heterogeneous mixture was stirred at roomtemperature for 14 days with periodic monitoring of the reactionprogress by HPLC. At a point where the 7-ACA area % was <2% of the totalpeak area, methanol (6.0 ml, 147 mmoles, 2.0 equivalents) was addeddropwise and stirring was continued for an additional 30 minutes. Thecrude product was filtered, washed with fresh Freon TF (1×300 ml), andwas partially dried under suction for 15 minutes. The product wasfurther dried in vacuo at ambient temperature for 16 hours.

The crude product was slurried in 80 ml of deionized water. The pH waslowered to 0.50 by dropwise addition of concentrated HCl with goodstirring. Decolorizing carbon (20% by weight of the crude product) wasadded, and the mixture was stirred for an additional 45 minutes. Theslurry was vacuum filtered through diatomaceous earth, and the pad waswashed with deionized water. Isopropyl alcohol (IPA, 900 ml) was addeddropwise over a period of 1 hour to the aqueous phase with moderateagitation. The resulting slurry was stirred at 25° C. for 1 hour, cooledto 0°-5° C. and was stirred for an additional 1 hour. Filtration,washing with cold (0°-5° C.) 9/1 IPA/water (1×200 ml) and acetone (1×200ml) and drying at 25° C. in vacuo for 16 hours gave 15.5 g (63%) ofcrystalline(6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em:-4-carboxylate monohydrochloride.

Method C

As an adjunct to the procedure of Method B, imidazole (0.50 g, 7.3mmoles, 0.10 equivalent) was added to theN-methylpyrrolidine/iodotrimethylsilane/Freon TF slurry at 0°-5° C. Thismodification resulted in a modest increase in reaction rate as the 7-ACAlevel reached <2% of the total HPLC peak area after 10 days. Processingof the reaction mixture as described in Method B above afforded 14.7 g(60%) of crystalline (6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylc3-em-4-carboxylate monohydrochloride.

Method D

To a slurry of (6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em-4-carboxylateiodide in Freon TF (prepared according to Method A of Example 6; 20.0 ginput 7-ACA) at 0°-5° C. under a blanket of dry nitrogen was added 10 ml(246 mmoles, 3.35 equivalents) of methanol dropwise over 5 minutes(Temperature <9° C.). The resulting slurry was stirred at 0°-5° C. for15 minutes following the addition. Next, 50 ml of 3 N HCl (prepared byadding 250 ml of concentrated HCl to 756 ml of deionized water) wasadded dropwise over a period of 10 minutes. Following the addition, thecooling bath was removed and the mixture was stirred for 15 minutes. Thephases were separated, and the aqueous phase (brought to a volume of 100ml) was stirred for 30 minutes at ambient temperature with 4.0 g (20% ofweight of input 7-ACA) of decolorizing carbon. The slurry was filteredthrough 4.0 g of diatomaceous earth, and the pad was washed withdeionized water (1×10 ml). The aqueous volume was brought to 100 ml.

Crystallization Method 1: To 50 ml of the rich aqueous was added 250 ml(5 volumes) of acetone dropwise to precipitate the product. Theresulting slurry was stirred with ice water cooling for 1 hour, afterwhich time it was filtered under suction, washed with cold (0°-5° C.)5/1 acetone/water (2×40 ml) and acetone (1×40 ml) and was partiallydried under suction for 15 minutes. The product was further dried invacuo at ambient temperature for 15 hours to give 4.48 g (37%, based on50% of the theoretical yield for 20.0 g input 7-ACA) of colorless,crystalline(6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em-4-carboxylatemonohydrochloride.

Crystallization Method 2: To 50 ml of the rich aqueous was added 150 ml(3 volumes) of isopropyl alcohol (IPA) dropwise to precipitate theproduct. The resulting slurry was stirred with ice water cooling for 1hour, after which time it was filtered under suction, washed with cold(0°-5° C.) 9/1 IPA/water (2×40 ml) and acetone (1×40 ml), and waspartially dried under suction for 15 minutes. The product was furtherdried in vacuo at ambient temperature for 15 hours to give 5.46 g (45%,based on 50% of the theoretical yield for 20.0 g input 7-ACA) ofslightly off-white, crystalline(6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em-4-carboxylatemonohydrochloride.

Method E

To a solution of (6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-iodomethylceph-3-em-4-carboxylate indichloromethane (prepared according to Method B of Example 3) at 0°-5°C. under a blanket of dry nitrogen was added 1.21 ml (11.7 mmoles, 1.0equivalent) of dry, 97% N-methylpyrrolidine (dried over molecularsieves) dropwise such that the temperature was <10° C. Following theaddition, the slurry was stirred at 0°-5° C. for 15 minutes. Next, 0.95ml (23.5 mmoles, 2.0 equivalents) of methanol was added dropwise (<10°C.), and stirring was continued at 0°-5° C. for 15 minutes. The solidwas isolated by suction filtration, washed with methanol (1×50 ml),dichloromethane (1×50 ml) and was dried in vacuo at ambient temperatureto yield 2.65 g (76%) of crude(6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em-4-carboxylate(as the iodide salt) as a light tan solid. The 360 MHz ¹ H NMR spectrumof this material showed a mixture of Δ² and Δ³ isomers in a ratio of65/35, respectively.

Method F

To a solution of (6R,7R)-trimethylsilyl7-[((trimethylsilyl)oxy)carbonyl]amino-3-iodomethylceph-3-em-4-carboxylatein dichloromethane (prepared according to Example 4; 10.0 g input 7-ACA)at 0°-5° C. under a blanket of dry nitrogen was added 3.7 ml (35.7mmoles, 1.0 equivalent) of dry, 97% N-methylpyrrolidine (dried overmolecular sieves) dropwise such that the temperature remained <10° C.Following the addition, the dark solution was stirred for an additional15 minutes at 0°-5° C. After this time, 2.9 ml (71.4 mmoles, 2.0equivalents) of methanol was added dropwise (evolution of CO₂ noted),and the resulting slurry was stirred for 5 minutes. A total of 50 ml offresh dichloromethane was added, and the reaction mixture was filteredunder suction. The filter cake was washed with dichloromethane (3×50 ml)and was partially dried under suction for 20 minutes. Further drying invacuo at ambient temperature for 17 hours gave 12.61 g (83%, as thehydriodide salt) of a 6/1 Δ² /Δ³ mixture (HPLC area % ratio) of(6R,7R)-trimethylsilyl7-amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em-4-carboxyate.

EXAMPLE 7(6R,7R)-7-Amino-3-[(1H-1-methyltetrazol-5-yl)thio]methylceph-3-em-4-carboxylicAcid Method A

To a stirred solution of (6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-iodomethylceph-3-em-4-carboxylate in Freon TF(prepared according to Method A of Example 3; 2.50 input 7-ACA) at 0°-5°C. under a blanket of dry nitrogen was added a solution of 1.07 g (9.2mmoles, 1.0 equivalent) of 1H-1-methyl-5-mercaptotetrazole and 0.74 ml(9.2 mmoles, 1.0 equivalent) of dry pyridine (dried over KOH) in 20 mlof dry dichloromethane (from sieves) dropwise over 10 minutes. Theresulting mixture was stirred at 0°-5° C. for an additional 30 minutesfollowing the addition. After this time, 1.5 ml (37 mmoles, 4.0equivalents) of methanol was added dropwise over 10 minutes, andstirring was continued for an additional 10 minutes at 0°-5° C. Thesolid was collected by suction filtration, washed with fresh Freon TF(2×10 ml) and dried to constant weight in vacuo to yield 3.4 g (>100%)of crude product.

This material was slurried in 10 ml of water, cooled to 0°-5° C. and thepH was lowered to 0.50 by dropwise addition of 4 N HCl solution. To theresulting cloudy solution was added 0.50 g of decolorizing carbon, andstirring was continued for 15 minutes. The slurry was filtered throughdiatomaceous earth, and the pad was washed with water (1×5 ml). Thefiltrate was cooled to 0°-5° C. and the pH was raised to 4.0 by dropwiseaddition of 6 N NaOH solution. The resulting slurry was stirred for 1hour at 0°-5° C. The solid was collected by suction filtration, washedwith cold (0°-5° C.) water (2×5 ml) and was dried to constant weight invacuo to give 1.3 g (43%) of 7-amino-3-[(1H-1-methyltetrazole-5-yl)thio]methylceph-3-em-4-carboxylic acid. The360 MHz ¹ H NMR spectrum and HPLC chromatogram of this material wereconsistent with those of an authentic sample prepared independently.

Method B

To a stirred solution of (6R,7R)-trimethylsilyl7-[((trimethylsilyl)oxy)carbonyl]amino-3-iodomethylceph-3-em-4-carboxylatein dichloromethane (prepared according to Example 4; 5.0 g input 7-ACA)at 0°-5° C. under a blanket of dry nitrogen was added a suspensionconsisting of 2.13 g (18.4 mmoles, 1.0 equivalent) of1H-1-methyl-5-mercaptotetrazole and 1.49 ml (18.4 mmoles, 1.0equivalent) of dry pyridine (dried over KOH) in 20 ml of dichloromethanedropwise over 5 minutes. The mixture was stirred for an additional 90minutes at 0°-5° C. following the addition. After this time, 2.50 ml(61.5 mmoles, 3.35 equivalents) of methanol was added dropwise over 2minutes (CO₂ evolution noted). The resulting slurry was stirred at 0°-5°C. for an additional 15 minutes, after which time it was filtered undersuction. The collected solid was washed with fresh dichloromethane (2×20ml) and was dried in vacuo at ambient temperature for 23 hours to give8.58 g (>100%) of crude product.

This material was slurried in 40 ml of deionized water, and the pH waslowered to 0.50 by the addition of 4 N HCl solution. Decolorizing carbon(0.86 g, 10% by weight of crude material) was added, and the resultingslurry was stirred at ambient temperature for 15 minutes. The charcoalwas removed by filtration through diatomaceous earth (2.0 g), and thepad was washed with water (1×5 ml). The filtrate was cooled to 0°-5° C.,and the pH of the aqueous was raised to 4.0 by dropwise addition of 6 NNaOH solution. After stirring the resulting slurry at 0°-5° C. for 90minutes, the solid was filtered, washed with cold (0°-5° C.) water (1×10ml) and was dried in vacuo at ambient temperature for 66 hours. A totalof 3.81 g (63%) of(6R,7R)-7-amino-3-[(1H-1-methyltetrazol-5-yl)thio]methylceph-3-em-4-carboxylicacid was isolated as an off-white solid. The 360 MHz ¹ H NMR and IRspectra, and the HPLC chromatogram (86.0% activity versus the standardlot) were consistent with an authentic sample of this material preparedindependently.

EXAMPLE 8(6R,7R)-7-Amino-3-[5-methyl-1,3,4-thiadiazol-2-yl)thio]methylceph-3-em-4-carboxylicAcid Method A

To a slurry of 1.22 g (9.2 mmoles, 1.0 equivalent) of2-mercapto-5-methyl-1,3,4-thiadiazole and 0.74 ml (9.2 mmoles, 1.0equivalent) of dry pyridine (dried over KOH) in 20 ml of drydichloromethane (dried over molecular sieves) at 0°-5° C. under ablanket of dry nitrogen was added a solution of (6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-iodomethylceph-3-em-4-carboxylate (preparedaccording to Method A of Example 3; 2.50 g input 7-ACA) in Freon TF overa period of 10 minutes with good stirring. The resulting mixture wasstirred at 0°-5° C. for 90 minutes following the addition. Next, 1.5 ml(37.0 mmoles, 4.0 equivalents) of methanol was added dropwise and theresulting slurry was stirred for an additional 10 minutes at 0°-5° C.The solid was collected by suction filtration, washed with fresh FreonTF (2×10 ml) and was dried to constant weight in vacuo to give 4.0 g(>100%) of crude product.

This material was suspended in 10 ml of water and was cooled to 0°-5° C.The pH was lowered to 0.30 by dropwise addition of concentrated HClsolution. To the resulting cloudy solution was added 0.40 g (10% byweight of crude) of decolorizing carbon, and stirring was continued at0°-5° C. for 15 minutes. The charcoal was removed by filtration and thepH of the clear, yellow filtrate was raised to 3.0 at 0°-5° C. bydropwise addition of solution. The resulting slurry was stirred at 0°-5°C. for 30 minutes. Suction filtration of the solid followed by washingwith cold (0°-5° C.) water (2×5 ml) and drying to constant weight invacuo gave 1.6 g (50%) of(6R,7R)-7-amino-3-[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methylceph-3-em-4-carboxylicacid. The 360 MHz ¹ H NMR spectrum and HPLC chromatogram of thismaterial were consistent with those of an authentic sample preparedindependently.

Method B

To a stirred solution of (6R,7R)-trimethylsilyl7-[((trimethylsilyl)oxy)carbonyl]amino-3-iodomethylceph-3-em-4-carboxylatein dichloromethane (prepared according to Example 4; 5.0 g input 7-ACA)at 0°-5° C. under a blanket of dry nitrogen was added a suspensionconsisting of 2.43 g (18.4 mmoles, 1.0 equivalent) of2-mercapto-5-methyl-1,3,4-thiadiazole and 1.49 ml (18.4 mmoles, 1.0equivalent) of dry pyridine (dried over KOH) in 20 ml of drydichloromethane (dried over molecular sieves) over a period of 5minutes. After stirring an additional 3.5 hours at 0°-5° C., a total of2.5 ml (61.5 mmoles, 3.35 equivalents) of methanol was added (CO₂evolution noted), and stirring was continued at 0°-5° C. for anadditional 15 minutes. The solid was collected by suction filtration,was washed with fresh dichloromethane (2×20 ml) and was dried in vacuoat ambient temperature for 19 hours to yield 9.30 g (>100%) of crudeproduct.

Processing of this crude material as described previously for the crudematerial of Method B of Example 7 afforded 3.81 g (60%) of(6R,7R)-7-amino-3-[(5-methyl-1,3,4-thiadiazol-2-yl)thio]methylceph-3-em-4-carboxylicacid. The 360 MHz ¹ H NMR and IR spectra, and the HPLC chromatogram(80.8% activity versus the standard lot) were consistent with anauthentic sample of this material prepared independently.

EXAMPLE 9(6R,7R)-7-Amino-3-[(1H-1,2,3-triazol-4-yl)thio]methylceph-3-em-4-carboxylicAcid Method A

This material was prepared exactly as described in Method A of Example 8except that (a) 1.13 g (9.2 mmoles, 1.0 equivalent) of1H-4-mercapto-1,2,3-triazole monosodium salt was used in place of the2-mercapto-5-methyl-1,3,4-thiadiazole, and (b) the slurry of thetriazole and pyridine in dichloromethane was added to the solution of(6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-iodomethylceph-3-em-4-carboxylate in Freon TF.The crude product obtained (3.5 g, >100%) was purified as previouslydescribed in Method A of Example 7, to yield 1.4 g (49%) of(6R,7R)-7-amino-3-[(1H-1,2,3-triazol-4-yl)thio]methylceph-3-em-4-carboxylicacid. The 360 MHz ¹ H NMR spectrum and HPLC chromatogram were consistentwith an authentic sample of this material prepared independently.

Method B

This material was prepared exactly as described in Method B of Example 7except that 2.26 g (18.4 mmoles, 1.0 equivalent) of1H-4-mercapto-1,2,3-triazole monosodium salt was used in place of the1H-5-mercapto-1-methyltetrazole. The crude product obtained (8.40g, >100%) was purified as previously described in Method B of Example 7,to give 3.25 g (56%) of(6R,7R)-7-amino-3-[(1H-1,2,3-triazol-4-yl)thio]methylceph-3-em-4-carboxylicacid. The 360 MHz ¹ H NMR and IR spectra, and the HPLC chromatogram(79.0% activity versus the standard lot) were consistent with anauthentic sample of this material prepared independently.

EXAMPLE 10(6R,7R)-7-Amino-3-[(1H-1-carboxymethyltetrazol-5-yl)thio]-methylceph-3-em-4-carboxylicAcid Method A

This material was prepared exactly as described previously in Method Aof Example 8 except that 1.47 g (9.2 mmoles, 1.0 equivalent) of1H-1-carboxymethyl-5-mercaptotetrazole was used in place of the2-mercapto-5-methyl-1,3,4-thiadiazole. A sample (3.25 g) of the crudeproduct obtained (4.6 g, >100%) was purified as previously described inMethod A of Example 8 to give 0.90 g (37%) of (6R,7R)-7-amino-3-[(1H-1-carboxymethyltetrazol-5-yl)thio]methylceph-3-em-4-carboxylic acid. The360 MHz H NMR spectrum and HPLC chromatogram were consistent with anauthentic sample of this material prepared independently.

Method B

This material was prepared exactly as described in Method B of Example 7except that (a) 2.94 g (18.4 mmoles, 1.0 equivalent) of1H-1-carboxymethyl-5-mercaptotetrazole was used in place of the1H-1-methyl-5-mercaptotetrazole, and (b) the reaction mixture wasstirred for 4.5 hours at 0°-5° C. before quenching with 2.5 ml (61.5mmoles, 3.35 equivalents) of methanol. The crude product obtained (11.03g, >100%) was purified as previously described in Method B of Example 7to afford 3.69 g (54%) of(6R,7R)-7-amino-3-[(1H-1-carboxymethyltetrazol-5-yl)thio]methylceph-3-em-4-carboxylicacid. The 360 MHz ¹ H NMR and IR spectra, and the HPLC chromatogram(79.6 area % purity; reference standard not available) were consistentwith an authentic sample of this material prepared independently.

EXAMPLE 11 (6R,7R)-7-Amino-3-(pyridinio)methylceph-3-em-4-carboxylicAcid Dihydrochloride Method A

To a stirred solution of (6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-iodomethylceph-3-em-4-carboxylate in Freon TF(prepared according to Method A of Example 3; 2.50 g input 7-ACA) at0°-5° C. under a blanket of dry nitrogen was added a solution of 1.6 ml(20.0 mmoles, 2.2 equivalents) of dry pyridine (dried over KOH) in 5 mlof dry Freon TF (dried over molecular sieves) dropwise over a period of10 minutes. The reaction mixture was stirred for an additional 15minutes following the addition. After this time, 1.5 ml (37.0 mmoles,4.0 equivalents) of methanol was added dropwise, and the slurry wasstirred at 0°-5° C. for 15 minutes. The solid was collected by suctionfiltration, washed with fresh Freon TF and dried to constant weight invacuo to give 3.0 g of crude product. The presence of the desired(6R,7R)-7-amino-3-(pyridinio)methylceph-3-em-4-carboxylate (as thehydroiodide salt) in this crude material was verified by comparison ofthe 360 MHz ¹ H NMR spectrum and HPLC chromatogram (34 area % purity)with those of an authentic sample of this material preparedindependently; see also Smith, G. C. D., EP 70706, Jan. 26, 1983; pg.21.

Method B

To a stirred solution of (6R,7R)-trimethylsilyl7-[((trimethylsilyl)oxy)carbonyl]amino-3-iodomethylceph-3-em-4-carboxylatein dichloromethane (prepared according to Example 4; 5.0 g input 7-ACA)at 0°-5° C. under a blanket of dry nitrogen was added a solution of 3.0ml (37.0 mmoles, 2.0 equivalents) of dry pyridine (dried over KOH) in 20ml of dry dichloromethane (dried over molecular sieves) dropwise over 5minutes. The resulting solution was stirred at 0°-5° C. for anadditional 90 minutes, after which time 2.5 ml (61.5 mmoles, 3.35equivalents) of methanol was added dropwise over 5 minutes such that thetemperature remained <10° C. (CO₂ evolution noted). The mixture wasstirred at 0°-5° C. for an additional 15 minutes. The solid was filteredunder suction, washed with fresh dichloromethane (2×20 ml) and waspartially dried under suction for 15 minutes. The solid was furtherdried at ambient temperature in vacuo for 17 hours to give 7.41 g (96%,as the iodide salt) of crude product.

This material was slurried in 25 ml of deionized water and the pH waslowered to 0.50 by dropwise addition of concentrated HCl solution. Atotal of 0.72 g of decolorizing carbon was added, and the resultingslurry was stirred at ambient temperature for 25 minutes. After thistime, the charcoal was removed by filtration through diatomaceous earth(1.0 g), and the pad was washed with water (1×5 ml). To the resultingclear filtrate was added 120 ml (4 volumes) of isopropyl alcoholdropwise with concomitant cooling to 0°-5° C. An additional 180 ml ofisopropyl alcohol (total=10 volumes) was added dropwise, and theresulting slurry was stirred at 0°-5° C. for 1 hour. The solid wascollected by suction filtration, washed with isopropyl alcohol (2×20 ml)and acetone (1×20 ml) and was partially dried under suction for 15minutes. Further drying at ambient temperature in vacuo for 16 hoursgave a 3.00 g (45%) of(6R,7R)-7-amino-3-(pyridinio)methylceph-3-em-4-carboxylatedihydrochloride. The 360 MHz ¹ H NMR spectrum and HPLC chromatogram (88area % purity) were consistent with an authentic sample of this materialprepared independently; see also Smith, G. C. D., EP 70706, Jan. 26,1983; pg. 21.

EXAMPLE 12 Attempted Preparation of(6R,7R)-7-Amino-3-(1-Methyl-1-pyrrolidinio)methylceph-3-em-4-carboxylateMonohydrochloride by Sequential Reaction of (6R,7R)-Trimethylsilyl7-(Trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate in FreonTF with Bromotrimethylsilane, N-Methylpyrrolidine and Aqueous HClSolution

To a stirred, slightly cloudy reaction mixture of (6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate (preparedaccording to Method A of Example 1; 10.0 g input 7-ACA) in Freon TF atambient temperature under a blanket of dry nitrogen was added 4.5 ml(42.2 mmoles, 1.15 equivalents) of 98% bromotrimethylsilane (Aldrich) ina slow stream over 1 minute. The progress of the reaction was monitoredby ¹ H NMR spectroscopy. After stirring 90 minutes at ambienttemperature, only a trace of the reaction products (3-bromomethylcephalosporin and trimethylsilyl acetate) were detected. The reactionwas gently heated at reflux under a blanket of nitrogen with reactionprogress again being monitored by ¹ H NMR spectroscopy. After 10 days,the predominant species in the reaction mixture were the startingmaterials. At best, only 15% (by intregration area) conversion to thedesired (6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-bromomethylceph-3-em-4-carboxylate te wasobserved by analysis of the reaction mixture by 360 MHz .sup. 1 H NMRspectroscopy.

EXAMPLE 13 Attempted Preparation of(6R,7R)-7-Amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em-4-carboxylateMonohydrochloride by Sequential Reaction of (6R,7R)-Trimethylsilyl7-(Trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate in FreonTF with Chlorotrimethylsilane, N-Methylpyrrolidine and Aqueous HClSolution

The procedure for this example was as described in Example 12, exceptthat 5.4 ml (42.2 mmoles, 1.15 equivalents) of chlorotrimethylsilane wasused in place of the bromotrimethylsilane. After heating the reaction atreflux for 10 days under a blanket of nitrogen, analysis of the mixtureby 360 MHz ¹ H NMR spectroscopy showed mainly chlorotrimethylsilane and(6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate. At best,only 5% (by integration area) conversion to the desired(6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-chloromethylceph-3-em-4-carboxylate wasobserved.

EXAMPLE 14(6R,7R)-7-Amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em-4-carboxylateHydrochloride or Hydroiodide Via a "One Pot" Reaction Scheme

The following is a compendium of experiences and observations derivedfrom several repeated reactions using the same amounts of reactants,temperatures, etc.

Procedure

1.7-ACA (50.0 g, 0.184 mole) was added into CCl₂ FCClF₂ (Freon TF) (350ml) under a nitrogen atmosphere (Note 1).

2. HMDS (46.5 ml, 0.22 mole, 1.2 equivalents) was added to this stirredsuspension in one portion.

3. TMSI (0.78 ml, 6.0 mmoles, 0.03 equivalent) was added in one portionby means of a syringe (Note 2).

4. The resulting mixture was heated and refluxed for 7-10 hours (Notes3, 4). The reaction was monitored by NMR (Note 5). CPD personnel will beresponsible for determining when the reaction is complete. Theappearance of the reaction mixture was a very thin, light yellow slurry.

5. The silylation mixture was cooled to ambient temperature, furtherdiluted with Freon TF (150 ml) and was cooled to 5° C. under a nitrogenblanket.

6. With good stirring, N-methylpyrrolidine, NMP, (26.83 ml, 0.26 mole,1.4 equivalents) was added over 10 minutes while maintaining a reactiontemperature below 10° C. (Note 6).

7. TMSI (47.1 ml, 0.33 mole, 1.8 equivalents) was added at a slow rateover a period of 10-15 minutes by syringe into the well-stirred mixturefrom Step 6 at 5° C. A small exothermic temperature rise was observedduring the TMSI addition. The reaction slurry was stirred at 5° C. for30 minutes under a blanket of dry nitrogen.

8. The resulting slurry was carefully heated and stirred at 35° C. to36° C. for a 45-55 hour period. The course of the displacement reactionwas monitored by HPLC (Note 7).

9. Both the volume of the reaction mixture and the rate of agitationwere checked regularly. An additional 100 ml of Freon TF was added asnecessary (Note 8).

10. Upon completion of the reaction (7-ACA less than 2 area % by HPLC),the slurry was cooled to 5° C. under nitrogen protection and methanol(25 ml, 0.615 mole) was added dropwise over an 8 minute period at 5° C.(Note 9).

11. The slurry thinned considerably and was stirred for an additional 15minutes at 5°-10° C. after methanol was added.

12. The cooling bath was then removed, and 125 ml of 3 N HCl (preparedby adding 250 ml of concentrated HCl solution to 756 ml of water) wasadded over 2 minutes with good stirring. The reaction temperature roseto 12°-15° C.

13. The hydrolysis mix was warmed to 20°-25° C. as fast as possible(without exceeding 25° C.) and was further stirred at 20°-25° C. for 15minutes.

14. The phases were separated, and the organic phase (bottom phase) wasback extracted with water (1×50 ml). This aqueous phase was used as thewash during the polish filtration of the rich aqueous solution.

15. Diatomaceous earth (2.5 g) was added to the rich aqueous phase fromStep 14 and it was filtered through a precoated diatomaceous earthfilter (7.5 g). The diatomaceous earth cake was washed with the aqueoussolution from Step 14 (back extraction) and then with 25 ml of deionizedH₂ O.

16. The combined rich aqueous solution and wash (volume ca. 270 ml,reddish brown in color) was stirred for 30 minutes at 21°-23° C. withdecolorizing carbon (10 g). Diatomaceous earth (2.5 g) was added to themixture and stirring was continued for 5 minutes.

17. The carbon was removed by filtration through a precoateddiatomaceous earth filter (7.5 g). The carbon cake was washed with water(1×75 ml), and was further dried under suction for 5 minutes.

18. If necessary, additional amounts of Freon TF found at the bottom ofthe rich aqueous solution were separated from the aqueous phase.

19. To the clear, orange colored aqueous solution (volume ca. 350 ml; pH0.9-1.15) was added isopropyl alcohol (Note 10) dropwise to the cloudpoint.

20. The isopropyl alcohol addition was stopped, and the crystallizationwas allowed to proceed at 21°-23° C. for 15 minutes.

21. After this time, additional isopropyl alcohol was added into theslurry over a period of 45 to 60 minutes (a total of 1.2 liters ofisopropyl alcohol was added), and then the slurry was stirred and cooledat 0°-5° C. for 60 minutes.

22. The product was collected by filtration, and the cake was washedwith cold (0°-b 5° C.) 9/1 isopropyl alcohol/water (2×100 ml, Note 11)and acetone (1×100 ml). The product (Note 12) was dried under suctionfor an additional 15 minutes. The product was then dried in vacuo toconstant weight to give 46-51 g (75-83%) of the crude HCl or HI salt ofthe title product (Compound I), as a slightly off-white to whitecrystalline solid. The activity yield was 60-63.4%.

23. The product purities were >95% based on NMR analysis. The HPLCpotencies were 750-800 mcg/mg versus an analytical sample of the Δ³ formof Compound I.HCl. The area % purities were >95%.

Note 1. 7-ACA is an extremely dusty solid. It should be weighed out in ahood or other area with adequate ventilation. A dust respirator anddisposable outer garment should be worn as protection from the 7-ACAdust.

Note 2. All operations with TMSI should be performed under anhydrousconditions as much as possible.

Note 3. The reaction time has proven to be variable and is probablydependent on the presence of TMSI (or its reactive equivalent) catalyst.If the reaction appears to be sluggish, additional TMSI hastens thecompletion of the reaction.

Note 4. It is important that vigorous reflux is maintained, as a majordriving force for reaction is the removal of the ammonia that isproduced.

Note 5. It is important that anhydrous conditions are maintained whensamples are removed from the reaction mixture. This holds true for allreactions in this sequence.

Note 6. A rise in temperature to over 10° C. during the addition of NMPresulted in an enhanced amount of the undesired Δ² isomer of 1/26.

Note 7. Samples should be submitted every 4-6 hours for HPLC evaluation.The reaction temperature, time and concentration and the number ofequivalents of TMSI and the medium basicity are critical in thisreaction.

Note 8. Slurry will become very thick and some dilution of CCl₂ FCClF₂will be required to facilitate agitation.

Note 9. Prior to the addition of CH₃ OH, the slurry is so thick thatchunks of material cling to the side of the reaction vessel, makingcomplete mixing with CH₃ OH difficult. It should be determined by visualobservation that good and completed mixing is occurring throughout thereaction vessel.

Note 10. This usually required 0.5-1.0 volume of isopropanol.

Note 11. This wash was prepared by mixing 90 ml of isopropanol and 10 mlof water and cooling to 0°-5° C. in an ice water bath.

Note 12. In a separate experiment, the product was isolated as the pureHI salt by treating the slurry from Step 11 with 125 ml of 3 N HIinstead of 125 ml of 3 N HCl (as in Step 12). Processing of the aqueousphase as described (cf. Steps 13-24) yielded 44.3 g of white,crystalline HI salt. The corrected HPLC potency was 105% versus ananalytical standard HCl salt. The activity yield from 7-ACA was 56.7%.

EXAMPLE 15 Recrystallization of(6R,7R)-7-Amino-3-(1-methyl-1-pyrrolidinio)-methylceph-3-em-4-carboxylateMonohydrochloride (Compound I.HCl) Procedure

1. Crude I.HCl (15.0 g, 0.045 moles) was added in one portion to 1N HCl(125 ml, 3.5 moles, 3.50 equivalents) with good stirring.

2. The resulting mixture was stirred at ambient temperature for 5minutes.

3. A total of 8.0 g of decolorizing carbon was added in one portion withcontinued good stirring. The slurry was agitated for an additional 45minutes.

4. The carbon slurry was filtered under suction through a pad ofdiatomaceous earth (8.0 g). The pad was washed with water (1×35 ml), andwas dried under suction for 5 minutes.

5. The slightly cloudy filtrate was polish filtered through a 5 μmMillipore filter to give a sparkling clear, water-white aqueous filtrate(volume=170 ml).

6. Isopropyl alcohol (125 ml) was added dropwise to the cloud point overa period of 25 minutes with good stirring. At this point, the additionof isopropanol was stopped. The slurry was stirred at ambienttemperature for 15 minutes, during which time a good seed bed wasestablished.

7. Additional isopropyl alcohol (475 ml, Note 3) was added dropwise overa period of 25 minutes with good stirring.

8. The resulting slurry was stirred with ice water bath cooling for 1hour.

9. The slurry was filtered, and was sequentially washed with cold (0°-5°C.) 9/1 isopropanol/water (2×120 ml, Note 4) and acetone (1×120 ml).

10. The filter cake was partially dried under suction for 15 minutes.Further drying in vacuo (steam injector suction) for 15 hours at 40° C.gave 7.87 g (52%) of snow-white, electrostatic, crystalline I.HCl (Note5).

Note 1. The number of moles of input I.HCl is based on 100% purity.

Note 2. The 1N hydrochloric acid solution was prepared by adding 83 mlof concentrated hydrochloric acid to 920 ml of distilled water.

Note 3. The total volume of isopropyl alcohol used for thecrystallization was 600 ml, which was 3.5 times the volume of thepolished aqueous filtrate from Step 5.

Note 4. The isopropanol/water washes consisting of 108 ml isopropanoland 12 ml distilled water were cooled to 0°-5° C. in an ice bath.

Note 5. The analytical data complied on the recrystallized I.HCl areshown below:

    ______________________________________                                        ANALYSIS THEORY    FOUND    CORRECTED FOR KF                                  ______________________________________                                        % C      46.77     46.02    46.71                                             % H       6.04     6.17     6.10                                              % N      12.59     12.31    12.49                                             % S       9.61     9.50     9.64                                              KF(H.sub.2 O)                                                                          --        1.47                                                       Residue  --        <0.1                                                       (sulfated ash)                                                                ______________________________________                                    

This material was assayed at 99.5% potency versus the HPLC standard lotof I.HCl. The Klett number was 3 (100.0 mg sample diluted to 10 ml in avolumetric flask with Milli-Q water; filtered through a Milex HPLCsample preparation filter; blue light; path length ca. 1.2 cm).

In general, it has been found that the "crude" compound I.HCl formed bythe addition of HCl to the final mixture, contains some I.HI (formedfrom the iodide present in the precursor intermediate II). Thus,although it is of high antibacterial purity, it normally must berecrystallized as above to remove Compound I.HI.

On the other hand, the initially crystallized Compound I.HI formed bythe addition of HI to the final reaction mixture, is free of CompoundI.HCl. Accordingly, the I.HI is normally of high purity and need not berecrystallized.

EXAMPLE 16 Conversion of I, (X=HCl) to (VIII)

A sample of Compound I (X=HCl), (21.72 g, 0.0612 mole), was dissolved inwater (190 ml) at 25° C. with stirring. The mixture was then cooled to8°-10° C., and the pH adjusted from 2.5 to 5.8 (range 5.7-5.9) by thedropwise addition of sodium hydroxide solution (2 N, 30.5 ml, 0.061mole, 1.0 equivalent). Total volume was 214 ml.

Tetrahydrofuran (THF, 555 ml) was then added in three portions. Thetemperature of the mixture after each addition rose to 12°-13° C. andwas allowed to return to 8°-10° C. before the next portion was added.The total addition time was 10 minutes. The pH of the mixture was5.8-6.1.

The pH of the mixture was then adjusted to 6.8 (range 6.7-6.9) by thedropwise addition of sodium hydroxide solution (2 N, 2.0 ml, 0.004mole).

A sample of the 1-benzotriazol(Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetate active ester (29.5 g,0.0927 mole) was added to the reaction mixture in five equal portionsover 45 minutes. The cooling bath was removed after the first portion ofthe active ester had been added. The pH of the reaction mixture wasreadjusted to 6.5 (range 6.5-6.7) 5-10 minutes after each addition ofthe active ester by the dropwise addition of sodium hydroxide solution(2 N).

The clear, pale orange reaction mixture was stirred for 2-3 hours at 25°C. In the initial 30 minutes, the pH was readjusted to 6.5 (range6.5-6.7) every 5-10 minutes by the dropwise addition of 2 N sodiumhydroxide solution. In the remaining reaction time, the pH wasreadjusted to 6.5 every 15 minutes (total 2 N NaOH: 29.5 ml, 0.059 mole,0.97 equivalent). The completion of the reaction was judged by HPLCanalysis.

Solids present in the reaction mixture were then removed by filtrationand washed with water (2×5 ml). The filtrate was extracted with methylisobutyl ketone (MIBK, 790 ml) and the aqueous layer separated. Theorganic phase was washed with water (64 ml), and the aqueous phasescombined and stirred with Dicalite (5.1 g) for 10 minutes. The solidswere removed by suction filtration and washed with water (2×5 ml).

The resulting clear orange solution (volume 314 ml) was acidified withgood stirring to pH 3.7 (range 3.5-4.0) by the dropwise addition ofsulfuric acid (4N, 14.5 ml). At this point the mixture became cloudy andcrystallization of the sulfuric acid addition salt of (VIII) began.

The crystallization was allowed to proceed for 10-15 minutes, and thenthe pH was adjusted to 3.0 (range 2.9-3.1) by the dropwise addition ofsulfuric acid (4N, 7.5 ml). The mixture was cooled to 0 to 5° C. and theremaining sulfuric acid (4N, 63.5 ml) was added over 20-30 minutes(resulting pH: 1.3-1.5). After the addition of sulfuric acid wascomplete, the slurry was stirred for 1 hour at 0 to 5° C.

The white crystalline product was removed by suction filtration andwashed with sulfuric acid (0.5N, 63.5 ml). The solids were partiallydried under suction for 15 minutes and then washed with acetone (2×100ml). The solids were again partially dried under suction for 10 minutesand then slurried for 1 hour in acetone (400 ml) with good agitation.The solids were removed by suction filtration, washed with acetone(2×100 ml) and dried in vacuo (10-15mm Hg) at 35°-40° C. to constantweight (3-6 hours).

The product, the sulfuric acid addition salt of (VIII), was recovered asa slightly electrostatic, white crystalline solid (28.79 g, 81.4%).

EXAMPLE 17 Conversion of I (X =HI) to (VIII)

The general procedure of Example 16 is repeated except that the I (X=HCl) starting material is replaced by an equimolar amount of I (X =HI),and the title compound is thereby produced.

Further Detailed Description of the Invention EXAMPLE 18(6R,7R)-Trimethylsilyl 7-(Trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate ##STR27##

An oven-dried flask and Friedrich's condenser were cooled to ambienttemperature under a stream of dry nitrogen. The flask was then chargedwith 10.0 g(36.7 mmoles) of 7-ACA (97.2% purity) and 70 ml of dry1,1,2-trichloro-trifluorethane (Freon TF, dried over molecular sieves).To the resulting slurry was added 9.3 ml (44.1 mmoles, 1.2 equivalents)of 98% 1,1,1,3,3,3-hexamethyl-disilazane (HMDS) and 0.16 ml (1.1 mmoles,0.03 equivalents) of iodotrimethylsilane (TMSI) by syringe with goodstirring and with protection from moisture. The slurry was vigorouslyheated under reflux for 7-10 hours with a slight nitrogen sweep throughthe system. The reaction was then cooled to ambient temperature under ablanket of dry nitrogen, and was diluted with 30 ml of fresh Freon TF. A^(l) H NMR spectrum of an aliquot of the slightly hazy reaction mixtureshowed >95% conversion to the desired product which is identical to theproduct of Example 1, and the ^(l) H NMR data is the same as reported inExample 1 Method A.

EXAMPLE 19(6R,7R)-7-Amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em-4-carboxylatemonohydroiodide ##STR28##

To a slightly hazy solution of (6R,7R)-trimethylsilyl 7-(trimethylsilyl)-amino-3-acetoxymethylceph-3-em-4-carboxylate in Freon TF (preparedaccording to Example 18) at 0°-5° C. under a blanket of dry nitrogen wasadded 5.35 ml (51.4 mmoles, 1.4 equivalents) of dry 97%N-methylpyrrolidine (dried over molecular sieves) dropwise over 1-2minutes with good stirring. Next, 9.40 ml (66.1 mmoles, 1.8 equivalents)of TMSI was added by syringe over about 5 minutes with continued goodstirring. The reaction temperature was kept below 10° C. during theaddition. The resulting slurry was stirred at 0°-5° C. for an additional30 minutes. After this time, the slurry was placed into an oil bathcarefully maintained at 35°-36° C. The progress of the reaction wasmonitored by HPLC. After 45-48 hours, the reaction was complete (<2 area% 7-ACA) and it was cooled to 0° 14 5° C. under a blanket of drynitrogen. A total of 5.0 ml (123 mmoles, 3.35 equivalents) of methanolwas added dropwise with good stirring. The reaction temperature wasmaintained at <10° C. during the addition. The resulting slurry wasstirred at 0°-5° C. for an additional 15 minutes. Next, 25 ml (75mmoles, 2.0 equivalents) of 3N aqueous HI solution was added in oneportion. Following the addition, the cooling bath was removed, and the 2phase mixture was rapidly warmed to 20°-25° C. Vigorous stirring wascontinued for 15 minutes. The phases were separated, and the organicphase was back extracted with water (1×10 ml). This back wash was savedfor later use.

The main aqueous phase was stirred at 20°-25° C. for 10 minutes with 0.5g of diatomaceous earth. The slurry was filtered through 1.5 g ofdiatomaceous earth (pre-washed with 50 ml water). The pad was washedwith the aqueous back wash from above, then with water (1×5 ml). Thecake was partially dried under suction for 5 minutes. A total of 2.0 gof decolorizing carbon was added and the slurry was stirred at 20°-25°C. for 30 minutes. After this time, 0.5 g of diatomaceous earth wasadded and stirring was continued for an additional 5 minutes. The slurrywas filtered through 1.5 g of diatomaceous earth (pre-washed with 50 mlwater), and the pad was washed with water (1×5 ml). The diatomaceousearth pad was partially dried under suction for 5 minutes. The filtratewas polish filtered through a 5 μm Millipore filter.

Precipitation of the product was achieved by dropwise addition of 3.5volumes of isopropanol to the clear, amber-colored aqueous phase at20°-25° C. The resulting slurry was cooled to 0°-5° C. and was allowedto stand for 1 hour. The slurry was filtered and washed with cold (0°-5°C) isopropanol/water (4/1;v/v) (2×20 ml) and acetone (2×20 ml). The cakewas partially dried under suction for 5 minutes. Further drying in vacuoat 20°-25° C. to constant weight afforded 8.94 g (57%) of white,crystalline (6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em-4-carboxylate monohydroiodide. HPLC showed the salt tobe 97 area % pure; and the 360 MHz ^(l) H NMR spectrum observed for thetitle compound as a monohydroiodide is the same as the ^(l) H NMR datareported for the HCl salt of the identical product in Example 6, MethodA.

EXAMPLE 20(6R,7R)-7-Amino-3-(4-methyl-4-morpholinio)methylceph-3-em-4-carboxylatemonohydroiodide ##STR29##

The title compound was prepared from a Freon TF solution of(6R,7R)-trimethylsilyl 7-(trimethylsilyl)amino-3-acetoxymethyceph-3-em-4-carboxylate (from 50.0 g input 7-ACA) asdescribed in Example 19, except that 28.3 ml (257 mmoles, 1.4equivalents) of dry N-methylmorpholine (dried over molecular sieves) wassubstituted for the N-methylpyrrolidine. The progress of the reactionwas monitored by HPLC and was found to be complete after 7-8 hours at35°-36° C. The reaction was worked up as described in Example 19(amounts of materials are multiplied by 5× due to increased batch size)to afford 36.0 g (41%) of slightly off-white crystalline6R,7R)-7-amino-3-(4-methyl morpholinio)methylceph-3-em-4-carboxylatemonohydroiodide. HPLC area % purity was >95%; ¹ H NMR (360 MHz, D₂ O)δ3.30(s, 3H, N-CH₃), 3.60(m, 4H, ##STR30## 3.68(d, 1H, J=10 Hz, --SCH₂--), 4.04(d, 1H, J=10 Hz, --SCH₂ --), 4.2 (m, 4H, ##STR31## 4.25 (d, lH,J=14 Hz, ##STR32## 4.93 (d, 1H, J=14 Hz, β-5.30 (d, 1H, J=5Hz, C-6β-lactam), 5.53 (d, 1H, J=5Hz, C-7 β-lactam);

IR (KBr) 3460, 1795 and 1600 cm⁻¹.

Anal. Calc'd for C₁₃ H₁₉ N₃ O₄ S.HI: C, 35.40; H, 4.34; N, 9.53; Found:C, 34.99; H, 4.38; N, 9.35;

EXAMPLE 21 (6R,7R)-7-Amino-3-(1-pyridinio)methylceph-3-em-4-carboxylatemonohydroiodide ##STR33##

The title compound was prepared from a solution of(6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-acetoxy-methyceph-3-em-4-carboxylate in FreonTF (10.0 g input 7-ACA) as described in Example 19, except that 4.2 ml(51.4 mmoles, 1.4 equivalents) of dry pryidine (dried over KOH) wassubstituted for the N-methyl-pyrrolidine. The progress of the reactionwas monitored by HPLC and was found to be complete after 51 hours at35°-36° C. The slurry was cooled to 20°-25° C. under a blanket of drynitrogen. The solid was removed by filtration through a funnel underpositive nitrogen pressure. The collected solid was washed with freshFreon TF (2×100 ml). The filtercake was quickly added to 50 ml of drydichloromethane which was pre-cooled to 0°-5° C. in an ice-water bath.To the resulting dark solution was added 5.0 ml (123 mmoles, 3.35equivalents) of methanol dropwise with good stirring and with a reactiontemperature of <10° C. The resulting slurry was stirred at 0°-5° C. foran additional 15 minutes. The solid was collected by filtration and waswashed with fresh CH₂ Cl₂ (2×50 ml). The filtercake was reslurried in150 ml CH₂ Cl₂ for 1 hour. The solid was filtered, washed with CH.sub. 2Cl₂ (2×50 ml) and dried in vacuo at 20°-25° C. to constant weight toafford 14.7 g (95%) of crude (6R,7R)-7-amino-3-(1-pyridinio)methylceph-3-em-4-carboxylate monohydroiodide. The 360 MHz ^(l) H NMRspectrum and HPLC chromatogram (65 area % purity; major contaminant waspyridine hydroiodide, 13 area %) of this material were consistent withan authentic sample prepared independently; see also Smith, G.C.D.,EP-70706, Jan. 26, 1983; pg. 21).

EXAMPLE 22(6R,7R)-7-Amino-3-[1-(2,3-cyclopenteno)pyridinio]methylceph-3-em-4-carboxylatemonohydroidide ##STR34##

The title compound was prepared from a solution of(6R,7R)-trimethylsilyl 7-(trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate in Freon TF (10.0 g input 7-ACA) as described inExample 19, except that 6.02 ml (51.4 mmoles, 1.4 equivalents) of2,3-cyclopentenopyridine (dried over molecular sieves) was substitutedfor the N-methylpyrrolidine. The progress of the reaction was monitoredby HPLC and was found to be complete after 52 hours at 35°-36° C.Work-up of the reaction mixture as described previously in Example 21afforded 13.2 g (78%) of crude(6R,7R)-7-amino-3-[1-(2,3-cyclopenteno)pyridinio]methylceph-3-em-4-carboxylatemonohydroiodide. The 360 MHz ¹ H NMR spectrum and HPLC chromatogram (92area % purity) of this material were consistent with an authentic sampleof this material prepared independently.

EXAMPLE 23(6R,7R)-7-Amino-3-[1-(2-acetoxy)ethyl-1-pyrrolidinio]methylceph -3-em-4-carboxylate monohydroiodide ##STR35##

The title compound was prepared from a solution of(6R,7R)-trimethylsilyl 7-(trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate in Freon TF (10.0 g input 7-ACA) as described inExample 19, except that 8.08 g (51.4 mmoles, 1.4 equivalents) ofN-(2-acetoxy)ethylpyrrolidine was substituted for theN-methylpyrrolidine. The progress of the reaction was monitored by HPLC.During the first 22 hours at 35°-36° C., the reaction mixture oiled out.After a total of 48 hours at 35°-36° C., no further consumption ofstarting material was evident. The reaction mixture was cooled to 0°-5°C. under a blanket of dry nitrogen. A total of 7.45 ml (184 mmoles, 5.0equivalent) of methanol was added dropwise as a solution in 50 ml ofFreon TF. A reaction temperature of <10° C. was maintained during theaddition. The resulting slurry was stirred for 3.5 hours at 0°-5° C.following the addition. The slurry was filtered under suction, and thefiltercake was washed with Freon TF (2×50 ml). Further drying in vacuoat 20°-25° C. to constant weight afforded 27.9 g (>100%) of crudeproduct. The presence of the desired(6R,7R)-7-amino-3-[1-(2-acetoxy)ethyl-1-pyrrolidinio]methylceph-3-em-4-carboxylatemonohydroiodide in this crude material was verified by comparison of the360 MHz ^(l) H NMR spectrum and HPLC chromatogram of this material withspectra of this material prepared by an independent procedure. The 360MHz ^(l) H NMR spectrum showed a Δ³ /Δ² product ratio of 1/1.7 as wellas a significant amount of the starting amine. The HPLC chromatogramshowed 24 area % of the desired Δ³ -isomer and 34 area % of the Δ²-isomer were present in the crude solid.

EXAMPLE 24(6R,7R)-7-Amino-3[1-2(trimethylsiloxy)ethyl-1-pyrrolidinio]-methylceph-3-em-4-carboxylatemonohydroiodide ##STR36##

The title compound was prepared from a solution of(6R,7R)-trimethylsilyl7-(trimethylsilyl)amino-3-acetoxymethylceph-3-em-4-carboxylate in FreonTF (10.0 g input 7-ACA) as described in Example 19, except that 9.63 g(51.4 mmoles, 1.4 equivalents) of N-(2-trimethylsiloxy)ethylpyrrolidinewas substituted for the N-methylpyrrolidine. The progress of thereaction was monitored by HPLC. The Δ³ /Δ² mixture of the title compundproduced was detected was the free OH compounds due to hydrolysis of theTMS ether during the chromatographic analysis. During the first 23 hoursat 35°-36° C., the reaction mixture oiled out. After a total of 30 hoursat 35°-36° C., no further consumption of starting material was evident.The reaction was worked up exactly as described in Example 23 to afford29.77 g (>100%) of crude product. The presence of the desired(6R,7R)-7-amino-3-[1-(2-trimethylsiloxy)ethyl-1-pyrrolidinio]methylceph-3-em-4-carboxylatemonohydroiodide in this crude material was verified by comparison of the360 MHz ^(l) H NMR spectrum and HPLC chromatogram of this material withspectra of this material prepared by an independent procedure. The 360MHz ^(l) H NMR spectrum showed a Δ³ /Δ² product ratio of 1/3.3 as wellas a significant amount of the starting amine. The HPLC chromatogramshowed 16 area % of the desired Δ³ -isomer and 60 area % of the Δ²-isomer were present in the crude solid.

EXAMPLE 257-[α-(2-Aminothiazol-4-yl)-α-(Z)-methoxyiminoacetamido]-3-[(1-methyl-1-pyrrolidinio)methyl]-3-cephem-4-carboxylate ##STR37##

A total of 12.76 g (30 mmoles) of(6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em-4-carboxylate monohydroiodide (prepared in Example 19) wassuspended in 87 ml of water with good stirring at 20°-25° C. The slurrywas cooled to 8°-10° C., and the pH was raised to 5.80 at 7° C. bydropwise addition of 13.0 ml (26 mmoles, 0.87 equivalents) of 2N sodiumhydroxide solution over a period of 35 minutes. Next, 555 ml oftetrahydrofuran was added, and the pH of the resulting solution wasincreased to 6.8 at 10° C. by dropwise addition of 1.9 ml (3.8 mmoles,0.13 equivalents) of 2N sodium hydroxide solution. The cooling bath wasremoved, and 29.5 g (92.7 mmoles, 1.5 equivalents) of the HOBT activeester of syn-2-(2-aminothiazol-4-yl) -2 -methoxyiminoacetic acid wasadded in two equal portions of 14.75 g each over 30 minutes. Followingeach addition, the pH was readjusted to 6.5 every 5-10 minutes, bydropwise addition of 2N sodium hydroxide solution. In the remainingreaction time, the pH was readjusted to 6.5 by dropwise addition of 2Nsodium hydroxide solution every 15 minutes (total 2N sodium hydroxideused was 28.6 ml (57.2 mmoles, 1.91 equivalents). The completion of thereaction was determined by HPLC analysis.

After 1.75 hours the dark solution was poured into 365 ml of methylisobutyl ketone, and the lower aqueous phase was separated. The organicphase was back extracted with water (1×30 ml). The combined aqueousphases were stirred 10 minutes at 20°-25° C. with 2.35 g of diatomaceousearth. The insoluble material was removed by suction filtration, and thefiltercake was washed with water (1×5 ml). The amber colored aqueousphase was polish filtered through a 5μm Millipore filter. The pH of thesolution was 6.40 at 17° C.

A total of 6.7 ml of 4N sulfuric acid was added dropwise with goodstirring to give a turbid solution of pH 3.82 at 18° C. Crystallizationof the product was allowed to proceed for 5 minutes with good stirring.An additional 3.5 ml of 4N sulfuric acid was added to give a slurry ofpH 3.09 at 20° C. The slurry was cooled to 0°-5° C. and a total of 30 mlof 4N sulfuric acid was added dropwise over 20 minutes. The resultingslurry was stirred for 1 hour at 0°-5° C. The precipitate was filteredand washed with 0.5N sulfuric acid (1×30 ml). The filtercake waspartially dried under suction for 15 minutes. After this time, the cakewas washed with acetone (2×50 ml), and was again partially dried undersuction for 15 minutes. The cake was reslurried in 200 ml of acetone at20°-25° C. or 1 hour. The salt was filtered, washed with acetone (2×50ml) and was partially dried under suction for 15 minutes. Further dryingin vacuo at 40° C. to constant weight gave 12.41 g (72%) of crystalline,slightly off-white title compound as its sulfate salt: ¹ HNMR (360 MHz,D₂ O with solvent suppression) δ 2.16-2.33 (envelope, 4H, ##STR38## 3.01(s, 3H, N-CH3), 3.45-3.64 (m, 5H, ##STR39## --SCH₂ --), 3.95 (d, 1H,J=17 Hz, --SCH₂ --), 4.04 (d, 1H, J=14 Hz, ##STR40## 4.08 (s, 3H,--OCH₃), 4.75 (d, 1H, J=14 Hz, ##STR41## 5.37 (d, 1H, J=5 Hz, C-6β-lactam), 5.86 (d, 1H, J=5 Hz, C-7 β-lactam), 7.16 (s, 1H, C-5thiazole).

Anal. Calc'd for C₁₉ H₂₄ N₆ O₅ S₂.H₂ SO₄ : C, 39.43; H, 4,53; N, 14.53;S, 16.63; Found: C, 39.40; H, 4.47; N, 14.39; S, 16.60

EXAMPLE 267-[α-(2-Aminothiazol-4-yl)-α-(Z)-methoxyiminoacetamido]-3-[(4-methyl-4-morpholinio)methyl]-3-cephem-4-carboxylate ##STR42## The title compound was preparedfrom 54.0 g (122 mmoles) of(6R,7R)-7-amino-3-(4-methyl-4-morpholinio)methylceph-3-em-4-carboxylatemonohydroiodide (prepared in Example 20) and 59.0 g (184 mmoles, 1.5equivalents) of syn-2-(2-aminothaizole-4-yl)-2-methoxyiminoacetic acidHOBT active ester by the procedure described in Example 25. A total of60.1 g (84%) of crystalline, white title compound as its sulfate saltwas prepared by this procedure: ^(l) H NMR (360 MHz, D₂ O/NaDCO₃) δ3.30(s, 3H, NCH₃), 3.55 (m, 5H, ##STR43## 4.05 (d, 1H, J=16 Hz, --SCH2--),4.10 (s, 3H, -OCH3 , 4.1 (m, 4H, ##STR44## 4.21 (d, 1 H, J=14 Hz,##STR45## 4.95 (d, 1 H, J=14 Hz, ##STR46## 5.47 (d, 1 H, J=5 Hz, C-6β-lactam), 5.96 (d, 1 H, J=5 HZ, C-7 ⊖-lactam), 7.10 (s, 1 H, C-5thiazole).

Anal. Calc'd for C₁₉ H₂₄ N₆ O₆ S₂ SO₄ : C, 38.37; H, 4.41; N, 14.13; S,16.18; Found: C, 38.16; H, 4.32; N, 14.08; S, 16.14 .

EXAMPLE 27

The following Table provides a summary of results for some of theExamples in the present invention. With the exception of compounds ofExamples 19 and 20, the reported data are for crude HI salts isolated byfiltration of the slurry obtained from the methanol quench. Compounds ofExamples 19 and 20 were isolated after quenching the methanol slurrywith aqueous 3N HI.

                  TABLE                                                           ______________________________________                                        Compound of                                                                            %         Δ.sup.3 -HPLC Area                                                                  Δ.sup.3 /Δ.sup.2 Ratio             Example No.                                                                            Yield     % Purity    HPLC.sup.a                                                                            NMR.sup.b                              ______________________________________                                        19       57        97          97/0    --                                     20       41        >95         >95/0   --                                     21       95         65.sup.c   65/6    --                                     22       78        92          92/0    --                                     23       >100.sup.d                                                                              24          24/34   1/1.7                                  24       >100.sup.d                                                                              16           16/60  1/3.3                                  ______________________________________                                         .sup.a Reported data is area % for each isomer in the HPLC chromatograms      of the isolated HI salt.                                                      .sup.b Reported data is the isomer ratio obtained by comparative              integration of a baseline resolved peak(s) for each isomer.                   .sup.c The major contaminant was the HI salt of pyridine (24 area %).         .sup.d The 360 MHz spectrum of the crude HI salt showed the major             contaminant to be unreacted starting amine.                              

Othe variations will be evident to those skilled in the art. Therefore,the scope of the invention is intended to be defined by the claims.

We claim:
 1. Stable, crystalline(6R,7R)-7-amino-3-(1-methyl-1-pyrrolidinio)methylceph-3-em-4-carboxylate hydroiodide which is substantially free ofthe Δ² isomer.